I know someone who converted to Judaism, yet throughout the whole process was telling me personally (so I can't tell the Rabbi) that she wasn't interested in keeping Torah AT ALL but was telling the Rabbis that she was. After the Geirus (conversion) she went back to behaving like a gentile.

Is she Jewish? Are her kids?

I can't ask the Rabbi in this case, as he will know who I am talking about. Whom can I go to for advice on what to do?

friend-of-ger, welcome to Judaism.SE, and thanks very much for sharing this question! Please note that, as it says in the FAQ and elsewhere, this site does not offer professional (particularly rabbinic) advice. Especially for a question as sensitive as this one, I strongly recommend that you plan your action with the personal guidance of a qualified rabbi, not based on anything you read on an internet forum. As such, I edited your question so that you're not asking the community what to do. Please take a look at the FAQ and at meta.judaism.stackexchange.com/questions/312 .
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Isaac MosesMar 23 '12 at 17:47

3

What precluded you from telling the rabbi? I would try to reach him first.
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Seth JMar 23 '12 at 18:46

Israeli rabbinic courts have attempted to nullify conversions by other courts where they considered that the convert was not sincere at the time of the conversion. The Rabbinical Council of America has objected: See http://blogs.jta.org/telegraph/article/2008/05/06/999936/rca-speaks-out-against-attempts-to-nullify-conversions. In favor of nulification is the thought that if one did not have the actual intent to keep the mitzvot at the time of conversion, then the conversion should be invalidated. The other view is that once you commit to being Jewish, G-d will judge you as if you were, and punish you for sins only a Jew can be punished for.

When such a conversion occurs and the person is female, it can possibly be brought back X generations in the future, and then it would be a great problem. By opposing the Rabbanut's right to object these 'conversions' now, uncertain future has been created for generations. In 80 years there may be no RCA anymore but another body, stricter on giyur standards, and some people may learn they are not Jewish - this is one of the worst things a person can go through, to loose identity. Oj! Edomite (insincere) converts bis?
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MichaelSSep 14 '14 at 2:12